NetworkTimeManager.cs

using UnityEngine;
using UnityEngine.Assertions;
using UnityEngine.Networking;
using Prototype.NetworkLobby;
using System.Collections;
using System.Collections.Generic;
using System;
using System.Reflection;
using Random = UnityEngine.Random;
using UnityEngine.UI;
using UnityEngine.Events;

public class NetworkTimeManager : NetworkBehaviour
{
	static public NetworkTimeManager i = null;

	public IntUnityEvent UEventColorFlip = new IntUnityEvent();

	[SyncVar]
	public int secondsRemaining;

	float _timeLeft; // how many msec left in the game
	TimeSpan _timeSpan;
	bool _clockRunning = false;

    void Awake()
    {
        i = this;
    }

	public override void OnStartServer ()
	{
		// empty stub as of Unity 5.4 (NOTE: called by NetworkIdentity.UNetStaticUpdate – since all
		// NetworkBehaviours must have a NetworkIdentity component, NetworkIdentity must implement a
		// static Update function that finds (all?) NetworkBehaviour scripts on it's game object and
		// makes all the callbacks at the appropriate times)
		base.OnStartServer (); 

		_timeLeft = Constants.MATCH_LENGTH_SEC;
		_clockRunning = true;
		Debug.Log (string.Format("NetworkTimeManager.OnStartServer: ", ""));
		ServerDebugUI.i.Log (string.Format("NetworkTimeManager.OnStartServer: player count = {0}",
			NetworkGameManager.i.players.Count));
	} 

	[ServerCallback]
	void Update()
	{
		if (!_clockRunning)
			return;

		// server keeps track of time
		_timeLeft -= Time.unscaledDeltaTime;
		_timeLeft = _timeLeft < 0f ? 0f : _timeLeft; // QUESTION: necessary safty-check?
		var sec = Mathf.FloorToInt (_timeLeft);

		// update secondsRemaining SyncVar
		if (sec != secondsRemaining) {
			// QUESTION: if we assign the same value to an int syncvar, will it become marked dirty?
			secondsRemaining = sec;

			// update colorIndex SyncVar every 60 sec (test network functionality via the GameTimeUI which will change its color) 
			if (secondsRemaining % 10 == 0)
			{
				int newIndex = Random.Range (0, 6);
				ServerDebugUI.i.Log (string.Format ("NetworkTimeManager.Update: invoking EventColorFlip ({0})", newIndex));

				// do with Rpc call
				RpcColorFlip(newIndex);
			}
		}

		// no more time updates required; for now, auto-shutdown the network when this happens 
		if (secondsRemaining == 0)
		{
			_clockRunning = false;

			// TODO, QUESTION: move below call into NetworkGameManager which should manage the entire game life-cycle
			StartCoroutine(NetworkGameManager.i.ReturnToLobby());
		}
	}

	void ClientColorFlip(int colorIndex)
	{
		UEventColorFlip.Invoke(colorIndex);
	}

	// NOTE: jsut use Rpc calls instead of SyncEvents; per a Unity employee on their forums, 
	// "SyncEvent has turned out to not be very useful" (LINK: http://goo.gl/Jv5KXe)
	[ClientRpc]
	void RpcColorFlip(int colorIndex)
	{
		if(UEventColorFlip != null)
		{
			UEventColorFlip.Invoke(colorIndex);
		}
	}
}